I've been living with this for some time, then this morning asked myself why I'm living with it. Could not come up with a good answer.

I have Win 7 Pro 64-bit. Lenovo W540, docked. Two Dell 23" monitors. Screen on my left is monitor #1. Screen on my right is monitor #2. I once made the mistake of dragging PSD over to the right monitor. Now, no matter what I try, whenever I start up PSD, the splash screen shows up on #1, the connections window and the main window show up on #2. I can drag them back of over of course, which is what I've been doing. But I suspect that deep in the internals of PSD's settings is something that tells it to home to monitor #2. Hoping you know where that is, so I can set it back to #1. Thanks!

Can you start regedit.exe and go to the following section?

HKEY_CURRENT_USER\Software\Allround Automations\PL/SQL Developer\Position

You can remove the "Monitor" key in this section to fix the issue. You can also remove the "Top", "Left", "Width" and "Height" keys.

What you probably should be able to do is to click Windows / Save Layout, after moving all the windows to the right places. You probably will not be able to affect where the splash will show up, but all the other windows should remember where they were placed (when you saved the layout) and go back to that on each fresh start of the app.

Thanks Marco!
I first tried just removing the value of the Monitor key. Didn't work.
Then I removed the Monitor key. Didn't work.
Then I removed all five keys, as you suggested. Finally when I bring up PSD, the splash, connection and main windows all appear on my home monitor.